The present invention relates to a process for the preparation of 5-amino-1,2,4-triazole-3-sulfonamides utilizing 5-amino-3-mercapto-1,2,4-triazole and/or 5-amino-3-chlorosulfonyl-1,2,4-triazole as starting materials or intermediates.
Many 5-amino-1,2,4-triazole-3-sulfonamides, their preparation, and their value as intermediates in the manufacture of substituted 1,2,4-triazolo[1,5-a]-pyrimidine -2-sulfonamide herbicides have been described in U.S. Pat. No. 4,734,123 and 4,755,212. The only process disclosed for preparing these intermediates, however, involves the degradation of 1,2,4-triazolo-[1,5-a]pyrimidine-2-sulfonamide compounds by oxidation to 5-acylamino-1,2,4-triazole-3-sulfonamides and subsequent hydrolysis. This process is very expensive because it involves the preparation and degradation of one 1,2,4-triazolo[1,5-a]pyrimidine-2-sulfonamide compound in order to obtain another 1,2,4-triazolo-[1,5-a]-pyrimidine-2-sulfonamide compound.
The discovery of more direct, lower cost methods for the preparation of intermediates useful in the manufacture of substituted 1,2,4-triazolo[1,5-a]-pyrimidine -2-sulfonamide herbicides would be of great interest.